<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <script>
        var num = 18;
        var num1 = num;
        console.log(num,num1);
        num1 = 20;
        console.log(num,num1);
        var obj = {
            name:'老曾',
            age:18
        }
        var obj2 = obj;
        console.log(obj.age,obj2.age);
        obj2.age = 20;
        console.log(obj.age,obj2.age);
        
    </script>
</body>
</html>